Capacitors, particularly interdigitated capacitors, and other two-pole electrical components or devices, are well known in the art of electrical components as exemplified in U.S. Pat. No. 4,831,494 to Arnold et al. Capacitors typically comprise parallel plates, which act as charge collectors and sources, with a dielectric there between. The function of capacitors is well known and further discussion is not warranted herein.
The capacitors are elements that are added to circuitry with primarily a singular function. The primary function being a source of energy for the circuit to function. In this application, it is counted on to provide a reserve of energy mounted on to circuit traces or to electronically filter noise from the input or power signal, and in itself does not contribute to the circuit charge or discharge path. In many cases, traces have to be extended from the direct path of the power delivery to connect to the capacitor.
Capacitors are applied in an array when there is a necessity for large quantities of power in short durations. The energy is stored in the array of capacitors until a near instantaneous release of energy is required at which point the array of capacitors, or portions of the array, are discharged to provide a power source to serve a useful function.
As with any electrical device there is an ever pressing and ongoing desire for miniaturization. Decoupling arrays are not immune to this desire and, in fact, are a major focus in the desire to decrease the size of components and equipment containing the components. The efforts directed at miniaturization are countered by the equally pressing desires to simplify circuit complexity and efforts to minimize manufacturing complexities. The more complicated the circuit traces become the more susceptible the finished product is to product defects. Similarly, with more complex manufacturing processes the losses due to errors increases as does the cost associated with inferior products or products requiring rework.
There has been no shortage of effort focused on component miniaturization as exemplified in commonly assigned U.S. Pat. No. 7,068,490 to Prymak. In spite of the intense effort to miniaturize arrays the effort has been thwarted by the spacing required between capacitors. FIGS. 1 and 2, for example, illustrate the typical substrate utilized for capacitors, or decoupling, arrays or other two-pole electrical components such as varistors. In each figure the pattern is interdigitated wherein the power and ground terminations, 901 and 902 respectively, are adjacent as in a checkerboard pattern. If a capacitor, as shown in FIG. 3, is mounted on the substrate the terminal power tab, 404, of one capacitor will be adjacent to the ground tab, 406, of the adjacent capacitor. Therefore, the spacing of adjacent capacitors must be sufficiently large to avoid electrical shorting between the power tab of one capacitor and the ground tab of the adjacent capacitor.
The conflicting desires to miniaturize electrical components, while still maintaining simple circuit traces and reasonable manufacturing capabilities, has lead to the current conundrum wherein large steps in further miniaturization are no longer possible. The present invention provides a unique approach through integrated design of the capacitor and circuit board such that a significant reduction in size can be achieved without electrical shorting and without the necessity of difficult designs and manufacturing processes.